Aquiring the correct Parts
Ensure the caliper codes are as shown:
And also the corresponding brake brackets:

Your 323 hubs should look like these. Note the brake bracket ears with the 12.3mm diameter. They will need to be drilled out larger later.

Prepare the 323 spindles
-Whack the old hubs out with a hammer and socket
-Drill out the bracket mounting holes on the spindles to the diameter of the large bolts. You will need a slow speed drill with metal drilling bits.
-Clean it up, paint it how you like

Prepare the brake brackets
-Initially the xedos brake brackets will not mount up as they clash with spindle.
-Get your angle grinder, shave off metal where it contacts until both holes line up.
-Put some assembly lube or some other coloured fluid on the spindle, try and line it up, then look at the bracket for where it's marked with fluid. This will show where needs more grinding.
-Don't worry, you're removing relatively little material, they will be still more than strong enough.
-Once you've ground enough off, test assemble the assembly. Make sure all bolts go all the way home.

Get it pressed together
-Take it to someone who can press in the bearings with the mx-3 4 stud hubs
-You may want to get new brake dust shields, I'm not running any at the minute.

Get them on the car
-As per manual
-When putting your wheel on, check the edge of the brake bracket doesn't scratch your wheels. If it does grind off the sharp edge. I found one side needed grinding, the other was perfect as is.

DavOr's test fit:

My setup installed:

Extra Swept area

Results/Notes
Stopping power has greatly improved, I was actually shocked at the difference. Biggest downside is that the stock discs remain. However, it does sweep more area, an extra 10mm or so towards the middle of the disc, and of course bigger pad surface are.

wytbishop from mx-3.com is working on an easy adapter plate to fit wilwood 4pots to this setup so stay tuned.